Lernanthropus kroyeri (Copepoda, Siphonostomatoida: Lernanthropidae) is a gill parasite found on the sea bass Dicentrarchus labrax. It was significantly present during spring and summer, agreeing with a period of increasing temperature. Due to this, it shows morphological modifications, which are studied through scanning electron microscopy. This study made it possible to reveal some superficial structures associated with the tegument, in particular, sensory structures and anchoring organs were studied to illustrate the possible functions of these structures. On the body surface, several types of epicuticular formations were identified: very plenty ones with a tubular or filamentous aspect, which provides the copepod with a considerable increase of cuticular surface in order to a better oxygen usage, and so improving respiratory processes through the integument ; the other type of cuticular formation consists of longer and more manifold expansions less abundant than the other ones , and they have mainly a sensory function. Uniciliated sensory structures, not mounted on papillae and protruding from pits, occur regularly on all body surfaces, except on antennae and maxillipeds. These receptors show variation in distribution and morphology.